‘Heartbeats’ may keep galaxies churning
Until now, astronomers haven’t been able to offer a full explanation for why the Milky Way and other galaxies produce new stars at a relative snail’s pace. While they have known for decades that high turbulence keeps huge clouds of hydrogen gas from condensing into stars, they haven’t identified all the causes of the galactic perturbations. In a coming report researchers in San Diego say they have discovered that a well-known, but overlooked source of heating?regular outbursts of ultraviolet radiation from clusters of very large, bright stars?may play a significant role in keeping the Milky Way’s gas continually stirred up.
Researchers in Britain have developed a drug they say could revolutionize the effectiveness of radiation on cancer. Radiotherapy is used to destroy cancer cells by zapping their DNA, thus disrupting their ability to function and reproduce. But like other cells in the body, cancer cells have a sort of DNA repair kit that can minimize these effects. The new drug disables the DNA repair process and allows radiotherapy to target tumors with “deadly accuracy.”